This invention relates to an high pressure fuel injection device for an engine and more particularly to an improved fuel control system for such a fuel injection device.
It is well recognized that a proper fuel injection device can be highly effective in controlling the fuel consumption and lowering emission of exhaust gases of internal combustion engines, particularly diesel engines. A widely used type of fuel injection nozzle is the accumulator type nozzle in which the valve member of the nozzle is contained within an accumulator chamber for controlling the flow of fuel from the nozzle port that extends from this accumulator chamber. The injection valve either has affixed to it or is associated with an actuating member that is slidably supported in a control chamber which is also pressurized with fuel at the same pressure as in the accumulator chamber. As a result, the balanced pressures hold the valve member in its closed position. However, a relief valve is provided for relieving the pressure in the control chamber and when this occurs the unbalanced pressure on the valve member causes it to open and eject the fuel in the accumulator chamber. This type of injection nozzle is extremely effective.
However, the amount of fuel discharge by such accumulator nozzles has been previously controlled by controlling either or both the pressure in the accumulator chamber and the rate of opening of the valve. These types of controls although effective are not capable of controlling the amount of fuel injection injected over a wide range as is required when the engine is used in applications such as automotive applications.
It is, therefore, a principal object of this invention to provide an improved accumulator type fuel injection device.
Is a further object of this invention to provide an improved control arrangement for controlling the amount of fuel discharge by an accumulator type fuel injection device.
It is yet a further object to this invention to provide a simple and yet effective control for controlling the degree of opening of the injection valve of an accumulator type fuel injection nozzle.